Electric switch operating means



March 25, 1958 A. F. BULGIN ELECTRIC SWITCH OPERATING MEANS Filed April13, 1954' 2 Sheets-Sheet 1 Inventor, Amma mam/ck fillLG/M March 25, 1958A. F. BULGIN 2,328,372

su zcmc swnca OPERATING MEANS Filed April 13; 1954 2 Sheets-Sheet 2 5O 0Inventor Tl/ K FKE'ER/(K M9146 W/ a xi? Attorney:

United States Patent 2,828,372 ELECTRIC SWITCH OPERATING MEANS ArthurFrederick Bulgin, Southend-on-Sea, England, as-

siguor to A. F. Bulgin & Company Limited, Essex, England, a Britishcompany Application April 13, 1954, Serial No. 422,892 Claims priority,application Great Britain April 20, 1953 8 Claims. (Cl. 200-17) Thisinvention relates to electric switches such as are operated by means ofa plunger or press button and is particularly concerned with suchswitches as operate with a snap action produced by an over-centremechanism operated by a plunger or button. It is, however, alsoconcerned with various other forms of switch which may be operated in asimilar way. These switches are often operated by means of an externallever which bears against the plunger or button and which is usually inthe form of a flexible lever fixed at one end to the switch casing andoperated by flexing about its fixed end. The operating characteristicsof the switch, particularly the force which has to be applied and theextent of movement necessary to operate it, depend on the length of thelever and the relative positions of its mounting and its point ofcontact with the plunger. The object of the present invention is toprovide an operating mechanism which avoids the flexing of the operatinglever and which can be readily adjusted or set for different operatingcharacteristics.

According to the present invention, the operating lever is pivoted and anumber of pairs of pivot points for the lever situated at ditferingdistances from the plunger or push button are provided in a pair ofparallel brackets fixed in relation to the casing of the switch. Thelever is arranged to be pivoted to any selected pair of pivot points sothat according to the pivots selected so the operating characteristicsof the switch may be varied at will. Thus it will be understood that notonly can the pivot points be chosen at will, but also the nature of theoper-- ating lever itself can be correspondingly selected to give a widevariety of types and operating characteristics of switch with a verysmall number of components.

Preferably the pivot points are constituted by opposite pairs of holesin the brackets co-operating with projecting pivots on the lever. Inthis way the lever is able to turn freely so that no flexing isrequired. In addition a single design of bracket can be used for avariety of switches with different plunger or button positions.

Switches of this kind are frequently of a flat or substantiallyrectangular construction and the two brackets can be mounted on oppositesides so that the switch is sandwiched between them and may be held bybolts and nuts. Thus the two brackets may be made identical, leading tosimplicity in manufacture and assembly. If a number of switches providedwith brackets in this way are to be mounted side by side each with apair of brackets, it is important that adjacent levers and their pivotsshall not interfere with one another. For this purpose, the holes may beformed in a portion of each bracket which is indented so that thedistance between opposite holes is slightly less than the width of theswitch. Thus when the pivots of the lever are inserted in position theywill not project beyond the sides of the switch and there is, no dangerof fouling an adjacent switch.

As an alternative, however, to securing the brackets to the side of theswitch, they may be secured to the surface 2,828,372 Patented Mar. 25,1958 ICC -of the casing from which the plunger or push button extends.In this case the brackets may be spaced inwardly from the sides of theswitch so that there is no danger of fouling an adjacent switch.

As already mentioned, a wide variety of operating levers may be usedwith the same pair of brackets. These levers may be very simplyconstructed, for example, from sheet material, the pivots being formedas narrow lateral extensions of the lever. If the lever is made ofmetal, it may be stamped from sheet and have strengthening, as by a rib,formed in it at the same time. The portion of the lever formed of sheetmaterial need only extend as far as its point of engagement with theoperating plunger or button; the remainder of the lever can be made ofwire or other suitable material and may be of any shape dictated by theoperating requirements of the switch.

Normally the width of the broadest part of the lever will only be suchas to give it sutiicient strength and to provide adequate bearingsurface for engagement with the operating plunger or button. If desired,however, the lever or part of it may be broadened out so as to extendacross two or more switches so as to operate them together; In this casethe brackets are mounted on the outer portions of the outer switches ofthe assembly. The lever may operate all the switches simultaneously orin sequence, the latter being achieved for example by means of one ormore tongues struck out of the plane of the lever.

If, however, it is desired to operate the switches independently,individual operating levers for the switches may be provided and thesemay be mounted either on a common spindle extending across the assembly,or .alternatively each switch may be provided with a pair of bracketsfor pivoting its operating lever. In either case, however, the operatinglevers may be controlled by cams on a common shaft extending across theassembly.

Examples of switches in accordance with the invention will now bedescribed in more detail by way of example with reference to theaccompanying drawings, in which:

Figure 1 is an elevation of one construction of switch;

Figure 2 is a plan view of the switch shown in Figure 1;

Figure 3 is a plan view of two switches of the kind shown in Figure Imounted side by side;

Figure 4 is an elevation of a modified form of switch;

Figure 5 is a plan view of the switch shown in Figure 4;

Figure 6 is a perspective view of an assembly of switches;

Figure 7 is an end view of the assembly shown in Figure 6; and

Figure 8 is a plan view of a somewhat modified form of assembly.

The switch shown in Figure l comprises a casing formed in two halves 1and 2, pierced by holes 3 and 4 through which securing screws or boltsmay be passed. The switch is operated by a plunger or button 5 and thedetails of the internal operating mechanism have no hearing on theinvention. The plunger 5 is operated by a lever 6, which is stamped fromsheet metal and is formed with a strengthening rib 7. As seen in Figure2, the lever is formed with a pair of projecting portions 8 whichconstitute its pivots. These pivots may be accommodated in any one of anumber of pairs of pivot points constituted by holes 9 formed inbrackets 10. These brackets are formed in one piece as a sheet metalmember of U section, of which the base is seen at 11 in Figure 2, andwhich is rivetted to the casing of the switch. It will be appreciatedthat by slightly springing the brackets apart the pivots 8 can beaccommodated in any of the pairs of holes to vary the pivot point of thelever. Thus it will be understood that in this way the operatingcharacteristics of the switch, that is to say, the pressure needed tooperate it and the amount of travel required for the operation, can bevaried at will over a considerable'range.

As shown the free end of the lever is bent upwardly, this being to suitthe particular operating requirements and method of use of the switch inquestion. It will also be understood that if the operating lever isremoved from the pivoted brackets, it can readily be replaced by anyother form of lever which may, for example, be straight or bent to anyrequired shape, or alternatively may be made of wire, be provided withan operating roller and so forth. By interchanging the operating lever awide range of different constructions of switch may be produced with aminimum of components.

As shown in Figure 3, two switches are mounted side by side, being heldtogether by screws passing through the holes 3 and 4 and secured by nuts16. In this case the brackets which are shown as 17 are not made as asingle U-piece but are L-section and rivetted independently by rivets 18to the casing of the separate switches. The brackets are, however,provided again with a number of holes 9' so as to provide a number ofpairs of pivot points for an operating lever 19. As shown, the operativeportion of this lever is made wide enough to act on both the plungers 5so as to operate both switches simultaneously. Again the operating leveris readily interchangeable and may have its pivoting adjusted at will tovary the operating characteristics of the switches. If, instead ofoperating the switches simultaneously it is required to operate theswitches in sequence, a tongue such as shown in dotted lines at 20 maybe struck out of the plane of the lever to act on one of the plungers 5.

The form of switch shown in Figures 4 and 5 is of a different generalconfiguration but is again controlled by means of a plunger operated bya lever 26. In this case the lever is shown as being stamped from sheetmetal, but again it will be appreciated that any one of a large varietyof operating levers could be used. The pivots of the lever areaccommodated in one of a number of pairs of holes 27 formed in bracketplates 28. In this case, the bracket plates are secured to the sides ofthe switch which is eifectively sandwiched between them as seen mostclearly in Figure 5. The brackets are held in position bymeans of screws29 fitted with nuts 30 and it will be understood that by the use oflonger screws a number of switches can readily be assembled side byside. In order to avoid possible fouling of the pivots of adjacentoperating levers, the holes 27 are formed in portions of the bracketplate 28, which are slightly indented, as shown at 31 in Figure 5, sothat the pivots of the levers do not project beyond the sides of theswitch. In this construction again the operating lever may readily besprung out of one pair of holes and replaced in another so as to varythe'operating characteristics of the switch at will. It will, of course,be understood also that, a common operating lever operating two or moreswitches assembled side by side as shown in Figure 3 could equally wellbe used with this construction of switch.

As shown in Figure 6, a number of switches of the same general kind asshown in Figures 4 and 5 are mounted side by side, being held togetherby screws 35 fitted with nuts 36. At each end of the assembly are a pairof bracket plates 37 and 33 provided with a number of holes 39. Theseholes accommodate a spindle at} which extends along the length of theassembly and carries the operating levers 41 for all the switches. Theseoperating levers in their turn are controlled by earns 42 mounted on acommon spindle 43 which extends between the bracket plate 37 and 38. Asshown, this is provided with an operating knob 44 and an indexingarrangementwhich consists of a spring ball which is pressed into holes45 in the plate 38.

r 2,828,372 e p I In each of the positions thus defined, one of the camsdepresses an operating lever 41 to operate one of the switches. Therotation of the common spindle is limited by a pin 46 working in apart-circular slot 47 in the plate 37. As shown the cams 42 are spacedat equal angular intervals around the spindle 43 so that the switchesare operated in succession. It will be understood, however, that thecams could be so arranged so that two or more of the switches could beoperated simultaneously and that moreover one cam could be arranged toextend over the width of more than one operating lever. As in all theother constructions, the operating characteristics of the switches maybe varied by moving the spindle 40 into one of the other pairs of holes39.

The assembly shown in Figure 8 represents a slight modification of thatshown in Figures 6 and 7. The main difference is that instead of acommon spindle 40, each operating lever 50 has its own individualpivots. In other words, this assembly represents a number of switchesshown in Figures 4 and 5 complete with their bracket plates 28 mountedside by side. It will be appreciated that in an assembly of this kind,very considerable fiexibility is possible. Thus operating levers 51 maybe adjusted independently so that the operating characteristics of theswitches may vary from switch to switch in the assembly. Also certain ofthe switches may be reversed in relation to one another. For example,the electrical terminal tags 51 may project in either direction and asshown two project one way and two the other. This may have certainadvantages in giving greater space for the electrical connections andmay also be arranged to suit the particular requirements of anindividual assembly.

The modification shown in Figure 8 is not provided with any indexingarrangement and the spindle which is shown as 52 may, for example, bedriven directly from a continuously rotating shaft, which may, forexample, form part of the machine. Thus as the machine is in operationso the various switches are operated in sequence at predetermined timeintervals. a

I claim:

1. In an electric switch having a casing, operating means comprising anoperating plunger extending through said casing, a lever adapted to bearfreely against said plunger, said lever having integral pivotingextensions, and resilient means secured to said casing and providing aplurality of pivotal mountings for said extensions, said pivotalmountings all being located on the same side of said plunger to give aplurality of leverageratios for said lever.

2. An electric switch according to claim 1, wherein said means providinga plurality of pivotal mountings comprises a pair of parallel brackets,said brackets being formed with opposite pairs of pivot holes. k

3. An electric switch according to claim 2, wherein said pair ofbrackets are formed in one piece as a sheet metal member of U-section..

4. In an electric switch having a casing of flat, substantiallyrectangular construction, the combination of an operating plungerextending through said casing, a pair of rectangular brackets, each ofsaid brackets including an indented portion having a plurality of holes,means mounting said brackets on opposite sides of said casing wherebythe holes in said brackets constitute pairs of pivotal mountings atdiffering distances from said plunger, and an operating lever formedwith pivots for seating in one of said pairs of pivotal mountings, saidlever thereby being adapted to bear against said plunger to operate saidswitch.

5. In an assembly comprising a plurality of plungeroperated .switchessecured side by side, each of said switches having an operating plungermeansassociated with it, operating means comprising pivoted lever meansengageable with the plunger means of the respective switches foroperating said switches, and a pair of brackets secured respectively tothe two outermost switches of said assembly, said brackets being formedwith a plurality of opposite pairs of holes to form a plurality of pivotpoints for said lever means.

6. An assembly according to claim 5, wherein said lever means comprisesa single lever extending across the plungers of all said switches.

7. An assembly according to claim 5, wherein said lever means comprisesa plurality of levers for operating said switches and a spindleextending between said pivot points, said spindle providing a mountingfor said levers.

8. In an assembly comprising a plurality of plungeroperated switches,each of said switches having an operating plunger means associated withit, operating means comprising a plurality of pivoted operating levers,means providing a plurality of pivotal mountings for each of saidlevers, each of said levers being engageable with a plunger means tooperate a switch, a control spindle extending across said levers and aplurality of cam means mounted on said spindle for rocking said levers.

References Cited in the file of this patent UNITED STATES PATENTS

